If you go to the Ruger website and use Adobe to blow up the drawing to 300%, you'll see that part #5, the indicator, has a through hole and is trapped by the blind pin.

The good news is that Ruger will sell you a new indicator, pin and spring.

If you really need to get the indicator out, you could use a cutoff wheel and Dremel to grind away the indicator until it pops off he pin. Then grab the pin through the slot with a small pair of long nose pliers and back it out of the hole.